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McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 16/17] rcutorture: Check GP completion at stutter end Date: Wed, 29 Aug 2018 14:47:49 -0700 X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180829214722.GA23411@linux.vnet.ibm.com> References: <20180829214722.GA23411@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18082921-0052-0000-0000-000003281C84 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00009636; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000266; SDB=6.01080727; UDB=6.00557487; IPR=6.00860713; MB=3.00023001; MTD=3.00000008; XFM=3.00000015; UTC=2018-08-29 21:47:57 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18082921-0053-0000-0000-00005DE5E2B9 Message-Id: <20180829214750.26972-16-paulmck@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-08-29_06:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=3 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1808290211 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The rcu_torture_writer() function invokes stutter_wait() at the end of each writer pass, which occasionally blocks for an extended time period in order to ensure that RCU can handle intermittent loads. But part of handling a busy period is invoking all the callbacks before the end of the idle period induced by stutter_wait(). This commit therefore adds a return value to stutter_wait() indicating whether stutter_wait() actually waited. In addition, this commit causes rcu_torture_writer() to test this value and if set, checks that all the elements of the rcu_tortures[] array have been freed up. Signed-off-by: Paul E. McKenney --- include/linux/torture.h | 2 +- kernel/rcu/rcutorture.c | 5 ++++- kernel/torture.c | 3 ++- 3 files changed, 7 insertions(+), 3 deletions(-) diff --git a/include/linux/torture.h b/include/linux/torture.h index 61dfd93b6ee4..48fad21109fc 100644 --- a/include/linux/torture.h +++ b/include/linux/torture.h @@ -77,7 +77,7 @@ void torture_shutdown_absorb(const char *title); int torture_shutdown_init(int ssecs, void (*cleanup)(void)); /* Task stuttering, which forces load/no-load transitions. */ -void stutter_wait(const char *title); +bool stutter_wait(const char *title); int torture_stutter_init(int s); /* Initialization and cleanup. */ diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index 7df8142a6a22..ae10ad531993 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -1144,7 +1144,10 @@ rcu_torture_writer(void *arg) !rcu_gp_is_normal(); } rcu_torture_writer_state = RTWS_STUTTER; - stutter_wait("rcu_torture_writer"); + if (stutter_wait("rcu_torture_writer")) + for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) + if (list_empty(&rcu_tortures[i].rtort_free)) + WARN_ON_ONCE(1); } while (!torture_must_stop()); /* Reset expediting back to unexpedited. */ if (expediting > 0) diff --git a/kernel/torture.c b/kernel/torture.c index 1ac24a826589..17d91f5fba2a 100644 --- a/kernel/torture.c +++ b/kernel/torture.c @@ -573,7 +573,7 @@ static int stutter; * Block until the stutter interval ends. This must be called periodically * by all running kthreads that need to be subject to stuttering. */ -void stutter_wait(const char *title) +bool stutter_wait(const char *title) { int spt; @@ -590,6 +590,7 @@ void stutter_wait(const char *title) } torture_shutdown_absorb(title); } + return !!spt; } EXPORT_SYMBOL_GPL(stutter_wait); -- 2.17.1